Various types of data-writable optical disk such as CD (Compact Disk) or DVD (Digital Versatile Disk) have been put into practical use. When data is written in the data-writable optical disk, the written data is immediately reproduced to verify whether the data has been recorded normally or not. When it is determined as a result of verification that there is a defect in a sector in which the data is written and the data has not correctly been recorded there, the data in such a sector is written in another sector. The series of operations described above is expressed as defect processing.
In the defect processing, data which can not be written in a defective sector is written in another sector (alternative sector). The data of the alternative sector is then recorded on the optical disk. Recording of data concerning the alternative sector is executed by an optical disk drive. Control for the defect processing may be executed utilizing the disk drive itself (expressed as defect processing using a disk drive), or it may be executed utilizing a computer connected to the disk drive (expressed as defect processing using a computer).
When the defect processing is executed using a disk drive, it is necessary to previously prepare an area (alternative area) in which records on management of the alternative sector are recorded and an area as an alternative sector in the optical disk. Resultantly, area which can be used for recording the data is reduced by the alternative area and altentative sector.
On the other hand, when the defect processing is executed using a computer, address of the defective area and data concerning an area as an alternative sector for the data which is originally to be written at the address are managed by the computer, and are written in an area decided by the computer when the defect processing comes to the end. Thus, it is not necessary to previously acquire an alternative area nor an alternative sector on the optical disk, and the influence over a recording capacity of the optical disk is rather small. However, the computer is required to access the disk drive many times, and hence the processing speed is lower as compared to the case when the defect processing is performed using the disk drive.
Conventionally whether the defect processing to be executed using a disk drive or using a computer is decided according to a type of the optical disk. For instance, in the case of an optical disk in which an application for use in a personal computer is written, since a high speed access is desired, the defect processing is executed using the disk drive. In the case of applications requiring a large quantity of data to be written in an optical disk and relatively little affected by a defect of data, the defect processing is preferably executed using the computer.
Concretely, for instance, in the case of the DVD-RAM (DVD-Random Access Memory), alternative area is previously acquired in the fixed state, and the defect processing is executed using the disk drive. In the case of CD-RW (Compact Disk- Rewritable) is the defect processing generally executed using a computer.
As described above, the defect processing is executed using the disk drive or using the computer according to a type of writable optical disk. Therefore, data is recorded with different formats in an optical disk in which the defect processing is executed using a disk drive and in an optical disk in which the defect processing is executed using a computer. Further, an optical disk dedicated to data reproduction is formatted based on other system in which the defect processing is not taken into considerations.
Further, there are various types of formats for an optical disk which correspond to other needs. For instance, in a format suited to high speed access, a set of “an address data area comprising successive pit arrays (pit ID section)”, “a data area comprising written mark arrays”, and “a gap area in which no data is written” is repeatedly formed on an optical disk.
In an optical disk used for so-called random access in which data stored in the same area may be rewritten (overwritten) thousand times or more by using a phase-change type of optical disk, there is provided a gap (for instance, 2 KB) between data each having a fixed length (for instance, 32 KB). This configuration is employed to provide an allowance enabling random shift of a position of data having a fixed length (for instance, random shift within a range of ±63 B).
As described above, there are various formats for optical disks currently available in correspondence to various conditions such as access time, application, and whether execution of the defect processing is required or not. Therefore, optical disk producers have produced optical disks based on various formats.
In order to produce optical disks based on various formats, however, it is required for each producer to have various types of production facilities. This disadvantageously increases the production cost of the optical disk. Further, a plan for production of optical disks and stock management become complicated, which is disadvantageous in improving cost performance of optical disks.
On the other hand, users which purchase optical disks are required to select optical disks each formatted with a form suited to a purpose of use or an application from various types of optical disks. To satisfy this requirement, the users are required to have a certain degree of knowledge concerning formats of optical disks.
In addition, in the format in which a set consisting of a pit ID section, a data area, and a gap area is repeatedly provided, the pit ID sections are provided at a specified gap between data areas. Because of this configuration, the data area is interrupted at a specified interval, which makes it difficult to continuously record data.
Further in the writable optical disk, it is desired that data once written therein can be reproduced with a disk drive dedicated to data reproduction. To reproduce data stored in an optical disk formatted with a form in which pit ID sections are provided at a prespecified gap with a disk drive dedicated to data reproduction, it is necessary to add a function for skipping the pit ID section in reading data to the disk drive. Namely, the data recorded in the optical disk as described above can not be reproduced with a disk drive dedicated to data reproduction.